[Mesa-dev] [PATCH] configure.ac: set -O0 on --enable-debug

[Emil Velikov]

Hi Miklós,

On 15 October 2017 at 18:46, Miklós Máté <mtmkls at gmail.com> wrote:
> Autoconf sets CFLAGS="-g -O2" by default.
>
> Signed-off-by: Miklós Máté <mtmkls at gmail.com>
> ---
>  configure.ac | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/configure.ac b/configure.ac
> index 62d33a1941..c833d258ed 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -522,6 +522,8 @@ if test "x$enable_debug" = xyes; then
>          fi
>          if ! echo "$CFLAGS" | grep -q -e '-O'; then
>              CFLAGS="$CFLAGS -O0"
> +        else
> +            CFLAGS=`echo $CFLAGS | sed -e s/-O./-O0/`
>          fi
>      fi
>      if test "x$GXX" = xyes; then
> @@ -530,6 +532,8 @@ if test "x$enable_debug" = xyes; then
>          fi
>          if ! echo "$CXXFLAGS" | grep -q -e '-O'; then
>              CXXFLAGS="$CXXFLAGS -O0"
> +        else
> +            CXXFLAGS=`echo $CXXFLAGS | sed -e s/-O./-O0/`

Being the person who added -O0 in the first place I have to agree with others.
I don't think this is a good idea. But let me try to explain it from
another angle:

Regardless of the build system used, a general rule should apply - the
user has the final say.
Namely: if the user has set a optimisation level/flags in C*FLAGS
those must be honoured.

Yes it may be a bit confusing, if the use asks for "debug" build, yet
they explicitly set -O2/etc.

HTH
Emil